﻿AMERICAN TERTIARY AND CRETACEOUS FOSSILS. 377 



on the sides almost to the base of the ventral plate, becoming gradually fainter until 

 they disappear ; cavity shallow, ventral edge sharp, interior marked by numerous 

 compound concentric ribs crossed by very faint longitudinal lines. 



Dimensions. — Length 1| inch, length of rostrum f in., width of the ventral plate 

 I inch, just above the base of the cavity. 



The specimen figured is in the Academy's collection, and is somewhat smaller than 

 the above measurements which were taken from a specimen now in the Smithsonian 

 collection. 



Locality. — Wheelock, Texas. 



This species resembles more nearly Sepia Cuvieri, Desh., of the Paris basin than 

 any other, but can readily be distinguished from it by the dorsal callosity, which in 

 our species is not so prominent, and is comparatively sharp, especially towards the 

 extremity nearest the rostrum. The roughening of the surface of the same portion 

 is, in the Paris species, transverse, while in ours it is longitudinal. The ventral plate 

 is one third smaller, in the present species, than in S. Cuvieri. 



MUREX. 



Subgenus ODONTOPOLYS, Gall. 



v" M. (Odontopolts) compsorhytis. PI. 67, fig. 16. Shell triangular; whorls six; 

 three squamose varices ; on the body whorl between the two varices which enclose 

 the aperature are two elongated nodes, on the angle of the whorl, between the next 

 two to the left there are three of these nodes, and in the remaining space there are 

 four, which in this last case extend*, on the top of the whorl to the suture, and to the 

 anterior extremity of the shell as distinct ribs ; these are crossed by a few delicate 

 revolving lines, spire acuminate, canal moderately long and nearly straight; aper- 

 ture narrow; two plates or folds on the columella, a small rudimentary tooth at the 

 posterior extremity of the mouth, on the inner lip ; outer lip thickened and with 

 seven or eight prominent heavy teeth. 



Dimensions. — Length "75 in., length of aperture "5 in., width of body whorl "45. 



Locality. — Wheelock, Texas. Collection of the Smithsonian Institution. 



This shell differs so materially from all the other Murices, that I propose to make it 

 the type of a new subgenus, as above. It resembles the subgenus Pteronotus in the 

 arrangement of the varices, but the folds on the columella and the crenulations of the 

 outer lip will serve to distinguish it. 



FUSUS, Klein, 



\ F. mortoniopsis. PI. 67, fig. 15. Scalariform; whorls eight, angular and jflbmi- 

 nent ; spire nearly as long as the aperture ; aperture elongated angular/ above, 



I proi 

 r/ abo" 1 



96 



